In the pharmaceutical industry, a machine for filling capsules with microtablets is known comprising a conveyor device movable continuously along a given path and having a number of pockets, each for housing a respective bottom shell of a capsule; a vibrating dispenser plate containing the microtablets; and a metering wheel mounted to rotate continuously about its substantially vertical longitudinal axis.
The metering wheel has a number of metering devices, each of which travels with the metering wheel along a portion of the path of the bottom shells, in time with a respective bottom shell, to transfer a given quantity of product from the vibrating dispenser plate into the bottom shell.
Each metering device comprises a metering chamber communicating with the vibrating dispenser plate and having a shutter movable between a closed position, in which the metering chamber is filled with a given quantity of microtablets, and an open position, in which the metering chamber communicates with the relative bottom shell to transfer the microtablets into the bottom shell.
Supply of the microtablets into the metering chamber is controlled selectively by a recirculating device located at the inlet of the metering chamber to recirculate the microtablets inside the vibrating dispenser plate and cut off supply to the metering chamber.
Known machines of the type described above have various drawbacks, mainly due to the fact that, given the shape, size, and random distribution of the microtablets inside the metering chambers, the metering chambers, and hence the relative bottom shells, may be supplied with different quantities of microtablets, thus impairing the production of capsules all containing the same quantity of microtablets.